I sympathize with your Best Buy frustration. It took an entire month to finally get them to accept my Gateway back after I refused to accept their "it's software related" excuse for my sound issue. I just got lucky and wore down the manager, who, by the end of the process was not pleasant at all and I won't be going to that store any more.
Regarding the Acer, I was able to take it back because it was within days of getting it. I am so glad I did. Your best best will likely be to just wear them out also, keep going up the ladder, and bring in a folder of all the people complaining about this issue. This may sound stupid to some, but trust me it works - when you go in with problems like this, look as professional as you can. I wear a suit and tie to work and if I ever have issues, I ALWAYS take care of them after leaving work while I'm still dressed up. I could easily go in in shorts, or after I leave the gym, but when dealing with a manager and a complaint, you get taken much more seriously if you look like someone whose got their act together rather than someone who is just left the gym and is sweaty. Just trust me on this my experience over the years has me convinced that it is half the battle of getting taken seriously.
Good luck on getting the Acer exchanged. Keeping going up the ladder as far as you can is all I can say.